Therapeutic methods using prostaglandin ep4 agonist components

ABSTRACT

Methods are provided directed to adminstering a therapeutically effective amount of a prostaglandin EP 4  agonist component to a mammal afflicted with or prone to affliction with a disease or condition selected from an esophageal ulcer, alcohol gastrophathy, a duodenal ulcer, non-steroidal anti-inflammatory drug-induced gastropathy, non-steroidal anti-inflammatory drug-induced enteropathy and intestinal ischemia. Such administration results in treating or preventing the disease or condition.

RELATED APPLICATION

This application is a continuation-in-part of U.S. patent application Ser. No. 11/291,694 filed Nov. 30, 2005, the disclosure of which is incorporated in its entirety herein by reference.

FIELD OF THE INVENTION

This invention relates to treating or preventing certain diseases or conditions using therapeutically active compounds. Particularly, this invention relates to methods using prostaglandin EP₄ agonist components to treat or prevent certain diseases or conditions.

BACKGROUND OF THE INVENTION Description of Related Art

Prostaglandins can be described as derivatives of prostanoic acid which have the following structural formula:

Various types of prostaglandins are known, depending on the structure and substituents carried on the alicyclic ring of the prostanoic acid skeleton. Further classification is based on the number of unsaturated bonds in the side chain indicated by numerical subscripts after the generic type of prostaglandin [e.g. prostaglandin E₁ (PGE₁), prostaglandin E₂ (PGE₂)], and on the configuration of the substituents on the alicyclic ring indicated by α or β [e.g. prostaglandin F_(2α) (PGF_(2β))].

Certain 10,10-dimethyl prostaglandins are known. These are described 10 in documents such as the following:

-   Donde, in United States Patent No. Patent Application Publication     No. 20040157901; -   Pernet et al in U.S. Pat. No. 4,117,014; -   Pernet, Andre G. et al., Prostaglandin analogs modified at the 10     and 11 positions, Tetrahedron Letters, (41), 1979, pp. 3933-3936; -   Plantema, Otto G. et al., Synthesis of     (.+−.)-10.10-dimethylprostaglandin E1 methyl ester and its     15-epimer, Journal of the Chemical Society, Perkin Transactions 1:     Organic and Bio-organic Chemistry (1972-1999), (3), 1978, pp.     304-308; -   Plantema, O. G. et al., Synthesis of 10,10-dimethylprostaglandin E1,     Tetrahedron Letters, (51), 1975, 4039; -   Hamon, A., et al., Synthesis of (+−)- and     15-EPI(+−)-10,10-Dimethylprostaglandin E1, Tetrahedron Letters,     Elsevier Science Publishers, Amsterdam, NL, no. 3, January 1976, pp.     211-214; and -   Patent Abstracts of Japan, Vol. 0082, no. 18 (C-503), Jun. 10, 1988     & JP 63 002972 A (Nippon lyakuhin Kogyo KK), 7 Jan. 1988;     the disclosures of these documents are hereby expressly incorporated     by reference.

United States Patent Application Publication 2004/0142969 A1, expressly incorporated by reference herein, discloses compounds according to the formula below

The application discloses the identity of the groups as follows:

-   m is from 1 to 4; n is from 0 to 4; A is alkyl, aryl, heteroaryl,     arylalkyl, arylcycloalkyl, cycloalkylalkyl, or aryloxyalkyl; E is     —CHOH— or —C(O)—; X is —(CH₂)₂— or —CH═CH—; Y is —CH₂—, arylene,     heteroarylene, —CH═CH—, —O—, —S(O)_(p)— where p is from 0 to 2, or     —NR^(a)— where R^(a) is hydrogen or alkyl; Z is —CH₂OH, —CHO,     tetrazol-5-yl, or —COOR^(b) where R^(b) is hydrogen or alkyl; and     R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ each independently are     hydrogen or alkyl.

U.S. Pat. No. 6,747,037, expressly incorporated by reference herein, discloses prostaglandin EP₄ agonists such as

U.S. Pat. No. 6,610,719, expressly incorporated by reference herein, discloses prostaglandin EP₄ selective agonists having the structure

The patent describes the identity of the groups as follows:

-   Q is COOR³, CONHR⁴ or tetrazol-5-yl; -   A is a single or cis double bond; -   B is a single or trans double bond; -   U is -   R² is α-thienyl, phenyl, phenoxy, monosubstituted phenyl or     monosubstituted phenoxy, said substituents being selected from the     group consisting of chloro, fluoro, phenyl, methoxy, trifluoromethyl     and (C₁-C₃)alkyl; -   R³ is hydrogen, (C₁-C₅)alkyl, phenyl or p-biphenyl; -   R⁴ is COR⁵ or SO₂R⁵; and -   R⁵ is phenyl or (C₁-C₅)alkyl.

10-Hydroxyprostaglandin analogues, that is natural prostaglandin EP₄ agonist compounds where the hydroxide is present on carbon 10 rather than carbon 11, are known in several patent documents including U.S. Pat. No. 4,171,375; U.S. Pat. No. 3,931,297; FR 2408567; DE 2752523, JP 53065854, DE 2701455, SE 7700257, DK 7700272, NL 7700272, JP 52087144, BE 850348, FR 2338244, FR 2162213, GB 1405301, and ES 409167; all of which are expressly incorporated by reference herein.

U.S. patent application Ser. No. 821,705, filed Apr. 9, 2004, expressly incorporated by reference herein, discloses compounds having the following structure

wherein

-   J is C═O br CHOH; -   A is —(CH₂)₆—, or cis —CH₂CH═CH—(CH₂)₃—, wherein 1 or 2 carbons may     be substituted with S or O; -   B is CO₂H, or CO₂R, CON R₂, CON HCH₂CH₂OH, CON(CH₂CH₂OH)₂, CH₂OR,     P(O)(OR)₂, CONRSO₂R, SONR₂, or -    each of R and R₂ is independently H or C₁₋₆ alkyl; -   D is —(CH₂)_(n)—, —X(CH₂)_(n), or —(CH₂)_(n)X—, wherein n is from 0     to 3 and X is S or O; and -   E is an aromatic or heteroaromatic moiety having from 0 to 4     substituents, said substituents each comprising from 1 to 6     non-hydrogen atoms as disclosed in the application.

Other compounds of interest are disclosed in U.S. Pat. No. 6,670,485; U.S. Pat. No. 6,410,591; U.S. Pat. No. 6,538,018; WO 2004/065365; WO 03/074483; WO 03/009872; WO 2004/019938; WO 03/103664; WO 2004/037786; WO 2004/037813; WO 03/103604; WO 03/077910; WO 02/42268; WO 03/008377 WO 03/053923; WO 2004/078103; and WO 2003/035064, all of which are expressly incorporated by reference herein.

Prostaglandin EP₄ selective agonists are believed to have several medical uses. For example, U.S. Pat. No. 6,552,067 B2, expressly incorporated by reference herein, teaches the use of prostaglandin EP₄ selective agonists for the treatment of “methods of treating conditions which present with low bone mass, particularly osteoporosis, frailty, an osteoporotic fracture, a bone defect, childhood idiopathic bone loss, alveolar bone loss, mandibular bone loss, bone fracture, osteotomy, bone loss associated with periodontitis, or prosthetic ingrowth in a mammal.”

U.S. Pat. No. 6,586,468 B1, expressly incorporated by reference herein, teaches that prostaglandin EP₄ selective agonists “are useful for the prophylaxis and/or treatment of immune diseases (autoimmune diseases (amyotrophic lateral sclerosis (ALS), multiple sclerosis, Sjoegren's syndrome, arthritis, rheumatoid arthritis, systemic lupus erythematosus, etc.), post-transplantation graft rejection, etc.), asthma, abnormal bone formation, neurocyte death, pulmopathy, hepatopathy, acute hepatitis, nephritis, renal insufficiency, hypertension, myocardial ischemia, systemic inflammatory syndrome, pain induced by ambustion, sepsis, hemophagocytosis syndrome, macrophage activation syndrome, Still's diseases, Kawasaki diseases, burns, systemic granuloma, ulcerative colititis, Crohn's diseases, hypercytokinemia at dialysis, multiple organ failure, shock, etc.”

Inflammatory bowel disease (IBD) is a group of diseases characterized by inflammation in the large or small intestines and is manifest in symptoms such as diarrhea, pain, and weight loss. Nonsteroidal anti-inflammatory drugs have been shown to be associated with the risk of developing IBD, and recently Kabashima and colleagues have disclosed that “EP₄ works to keep mucosal integrity, to suppress the innate immunity, and to downregulate the proliferation and activation of CD4+T cells. These findings have not only elucidated the mechanisms of IBD by NSAIDs, but also indicated the therapeutic potential of EP₄-selective agonists in prevention and treatment of IBD.” (Kabashima, et. al., The Journal of Clinical Investigation, April 2002, Vol. 9, 883-893).

Various other diseases or conditions of the mammalian body occur to the detriment of the individual affected. Among such diseases or conditions are esophageal ulcers, alcohol gastropathy, duodenal ulcers, non-steroidal anti-inflammatory drug-induced gastroenteropathy and intestinal ischemia. For example, there are approximately 100 million regular users of non-steroidal anti-inflammatory drugs (NSAIDs) in the world with 33 million in the United States alone. The number of users will increase with the increase in older population. One of the unavoidable side effects of NSAIDs is the risk of injury to the mucosal layer of the gastrointestinal (G.l.) tract, which may result in bleeding, erosion and/or ulcers. It has been estimated that among regular users of NSAIDs, about 30% experience such side effect.

New methods for treating or preventing such diseases or conditions would be highly beneficial.

SUMMARY OF THE INVENTION

The present invention relates to methods of treating or preventing one or more diseases or conditions, for example, of the mammalian body. Treating or preventing such disease(s) or condition(s) provides one or more substantial advantages, for example, enhances or maintains the health status of the individual, for example, human or animal, afflicted with or prone to affliction with such disease(s) or condition(s). The present methods are relatively easy to practice.

In one broad aspect of the invention, the present methods comprise administering a therapeutically effective amount of a prostaglandin EP₄ agonist component to a mammal afflicted with or prone to affliction with one or more diseases or conditions selected from an esophageal ulcer, alcohol gastropathy, a duodenal ulcer, non-steroidal anti-inflammatory drug-induced gastropathy, non-steroidal anti-inflammatory drug-induced enteropathy and intestinal ischemia, thereby treating or preventing the one or more diseases or conditions.

In one embodiment, the prostaglandin EP₄ agonist component is administered to a human. The prostaglandin EP₄ agonist component may be administered, for example, directly administered, to the gastrointestinal tract of a mammal, for example, a human.

Any and all features described herein and combinations of such features are included within the scope of the present invention provided that the features of any such combination are not mutually inconsistent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph illustrating the ability of a certain prostaglandin EP₄ agonist and prodrug to protect IEC-18 cells from indomethacin-induced apoptosis.

FIG. 2 is a graph illustrating the ability of a certain prostaglandin EP₄ agonist to inhibit indomethacin-induced apoptosis in gastric epithelial cells.

FIG. 3 is a graph illustrating the ability of a certain prostaglandin EP₄ agonist and prodrug to protect AGS cells from aspirin-induced apoptosis.

FIG. 4 is a graph illustrating the ability of a certain prostaglandin EP₄ agonist to reduce indomethacin-induced stomach lesions.

FIG. 5 is a graph illustrating the ability of a certain prostaglandin EP₄ agonist to mitigate indomethecin-induced stomach inflammation.

FIG. 6 is a series of two graphs illustrating some comparative results using a certain prostaglandin EP₄ agonist and misoprostol.

FIG. 7 is a graph showing a comparison between a certain prostagiandin EP₄ agonist and misoprostol with respect to BrdU labeling.

DETAILED DESCRIPTION

A prostaglandin EP₄ agonist is broadly defined as a compound which an ordinary person in the art reasonably believes agonizes a prostagiandin EP₄ receptor according to any one or more of numerous assays for determination of the EP₄ activity that are well known to those of ordinary skill in the art. Thus, such compounds may be considered prostaglandin EP₄ receptor agonists. While not intending to be limiting, one such assay is given hereinafter.

In one embodiment, the prostaglandin EP₄ agonist is selective for a prostaglandin EP₄ receptor relative to other prostaglandin receptor subtypes. In another embodiment, the prostaglandin EP₄ agonist is at least 10 times more active at the EP₄ receptor than at any other prostagiandin receptor subtype. In another embodiment, the prostaglandin EP₄ agonist is at least 100 times more active at the EP₄ receptor than at any other prostaglandin receptor subtype. In another embodiment, the prostaglandin EP₄ agonist is at least 1000 times more active at the EP₄ receptor than at any other prostaglandin receptor subtype. While not intending to be limiting, typical assays for the other receptor subtypes are also given hereinafter.

While not intending to limit the scope of the invention in any way, compounds according to the structures below are examples of prostaglandin EP₄ agonists or prostaglandin EP₄ agonist components:

pharmaceutically acceptable salts thereof; and prodrugs thereof,

-   wherein a dashed line represents the presence of absence of a bond; -   A is —(CH₂)₆—, cis —CH₂CH═CH—(CH₂)₃—, or —CH₂C≡C—(CH₂)₃—, wherein 1     or 2 carbon atoms may be substituted with S or O; or A is     —(CH₂)_(m)—Ar—(CH₂)_(o)— wherein Ar is interarylene or     heterointerarylene, the sum of m and o is from 1 to 4, and wherein     one CH₂ may be substituted with S or O; -   X is S or O; -   J is C═O, CHOH, or CH₂CHOH; and -   E is C₁₋₁₂ alkyl, R², or —Y—R² wherein Y is CH₂, S, or O; and R² is     aryl or heteroaryl.

In these structures, a dashed line represents the presence or absence of a bond. Thus, a structure such as the one below,

represents three different structures, depicted as follows.

In relation to the identity of A disclosed in the chemical structures presented herein, in the broadest sense, A is —(CH₂)₆—, cis —CH₂CH═CH—(CH₂)₃—, or —CH₂C═C—(CH₂)₃—, wherein 1 or 2 carbon atoms may be substituted with S or O; or A is —(CH₂)_(m)—Ar—(CH₂)_(o)— wherein Ar is interarylene or heterointerarylene, the sum of m and o is from 1 to 3, and wherein one CH₂ may be substituted with S or O.

While not intending to be limiting, A may be —(CH₂)₆—, cis —CH₂CH═CH—(CH₂)₃—, or —CH₂C≡C—(CH₂)₃—.

Alternatively, A may be a group which is related to one of these three moieties in which any carbon is substituted with S and/or O. For example, while not intending to limit the scope of the invention in any way, A may be an S substituted moiety such as one of the following or the like.

Alternatively, while not intending to limit the scope of the invention in any way, A may be an O substituted moiety such as one of the following or the like.

Alternatively, while not intending to limit the scope of the invention in any way, A may have both an O and a S substituted into the chain, such as one of the following or the like.

Alternatively, while not intending to limit the scope of the invention in any way, in certain embodiments A is —(CH₂)_(m)—Ar—(CH₂)_(o)— wherein Ar is interaryiene or heterointerarylene, the sum of m and o is from 1 to 4, and wherein one CH₂ may be substituted with S or O. In other words, while not intending to limit the scope of the invention in any way,

-   in one embodiment A comprises from 1 to 4 CH₂ moieties and Ar, e.g.     —CH₂—Ar—, —(CH₂)₂—Ar—, —CH₂—ArCH₂—, —CH₂Ar(CH₂)₂—,     —(CH₂)₂—Ar(CH₂)₂—, and the like; or -   A comprises O, from 0 to 3 CH₂ moieties, and Ar, e.g., —O—Ar—,     Ar—CH₂—O—, —O—Ar—(CH₂)₂—, —O—CH₂—Ar—, —O—CH₂—Ar—(CH₂)₂, and the     like; or -   A comprises S, from 0 to 3 CH₂ moieties, and Ar, e.g., —S—Ar—,     Ar—CH₂—S—, —S—Ar—(CH₂)₂—, —S—CH₂—Ar—, —S—CH₂—Ar—(CH₂)₂, and the     like.

Interarylene or heterointerarylene refers to an aryl ring or ring system or a heteroaryl ring or ring system which connects two other parts of a molecule, i.e the two parts are bonded to the ring in two distinct ring positions. Interarylene or heterointerarylene may be substituted or unsubstituted. Thus, an unsubstituted interarylene has 4 potential positions where a substituent could be attached. In one embodiment, Ar is substituted or unsubstituted interphenylene, interthienylene, interfurylene, or interpyridinylene. In one embodiment Ar is interphenylene (Ph). In one embodiment A is —(CH₂)₂-Ph-. While not intending to limit the scope of the invention in any way, substituents may have 4 or less heavy atoms, or in other words, non-hydrogen atoms. Any number of hydrogen atoms required for a particular substituent will also be included. Thus, the substituent may be hydrocarbyl having up to 4 carbon atoms, including alkyl up to C₄, alkenyl, alkynyl, and the like; hydrocarbyloxy up to C₃; CF₃; halo, such as F, Cl, or Br; hydroxyl; NH₂ and alkylamine functional groups up to C₃; other N or S containing substituents; and the like.

In one embodiment A is —(CH₂)_(m)—Ar—(CH₂)_(o)— wherein Ar is interphenylene, the sum of m and o is from 1 to 3, and wherein one CH₂ may be substituted with S or O.

In another embodiment A is —CH₂—Ar—OCH₂—. In another embodiment A is —CH₂—Ar—OCH₂— and Ar is interphenylene. In another embodiment, Ar is attached at the 1 and 3 positions, such as when A has the structure shown below.

In another embodiment A is —(CH₂)₆—, cis —CH₂CH═CH—(CH₂)₃—, or —CH₂C≡C—(CH₂)₃—, wherein 1 or 2 carbon atoms may be substituted with S or O; or A is —(CH₂)₂-Ph- wherein one CH₂ may be substituted with S or O.

In another embodiment A is —(CH₂)₆—, cis —CH₂CH═CH—(CH₂)₃—, or —CH₂C═C—(CH₂)₃—, wherein 1 or 2 carbon atoms may be substituted with S or O; or A is —(CH₂)₂-Ph-.

J is C═O, CHOH, or CH₂CHOH. Thus, while not intending to limit the scope of the invention in any way, compounds such as the ones below are useful as prostaglandin EP₄ agonists.

C₁₋₁₂ alkyl is alkyl having from 1 to 12 carbon atoms, including:

-   linear alkyl, such as methyl, ethyl, n-propyl, n-butyl, etc.; -   branched alkyl, such as iso-propyl, iso-butyl, t-butyl, isopentyl,     etc.; -   cyclic alkyl, such as cyclopropyl, cyclobutyl, cyclohexyl, etc.;     including -   substituted cycloalkyl, such as methylcyclohexyl, ethylcyclopropyl,     dimethylcycloheptyl, etc, and including moieties such as     CH₂-cyclohexyl, where the cyclic group is not the point of     attachment to the rest of the molecule; and any combination of the     other types of alkyl groups listed above. Thus, E may be any of     these groups. In particular, E may be linear alkyl of C₁₋₆,     especially butyl. Other particularly useful groups from which E may     be selected include, without limitation, cyclohexyl, cyclopentyl,     substituted cyclohexyl and cyclobutyl having less than 9 carbon     atoms, and the like.

E may be R² or Y-R² wherein Y is CH₂, S or O and R² is aryl or heteroaryl. Thus, E may be aryl, heteroaryl, —CH₂-aryl, —S-aryl, —O-aryl,—CH₂-heteroaryl, —S-heteroaryl, —O-heteroaryl, and the like.

Aryl is defined as an aromatic ring or ring system as well as a substituted derivative thereof, wherein one or more substituents are substituted for hydrogen. While not intending to limit the scope of the invention in any way, phenyl, naphthyl, biphenyl, terphenyl, and the like are examples of aryl.

Heteroaryl is defined as aryl having at least one non-carbon atom in an aromatic ring or ring system. While not intending to limit the scope of the invention in any way, in many cases one or more oxygen, sulfur, and/or nitrogen atoms are present. While not intending to limit the scope of the invention in any way, examples of heteroaryl are furyl, thienyl, pyridinyl, benzofuryl, benzothienyl, indolyl, and the like.

The substituents of aryl or heteroaryl may have up to 12 non-hydrogen atoms each and as many hydrogens as necessary. Thus, while not intending to limit the scope of the invention in any way, the substituents may be:

-   hydrocarbyl, such as alkyl, alkenyl, alkynyl, and the like, and     combinations thereof; -   hydrocarbyloxy, meaning O-hydrocarbyl such as OCH₃, OCH₂CH₃,     O-cyclohexyl, etc, up to 11 carbon atoms, and the like; -   hydroxyhydrocarbyl, meaning hydrocarbyl-OH such as CH₂OH, C(CH₃)₂OH,     etc, up to 11 carbon atoms, and the like; -   nitrogen substituents such as NO₂, CN, and the like, including -   amino, such as NH₂, NH(CH₂CH₃OH), NHCH₃, etc., up to 11 carbon     atoms, and the like; -   carbonyl substituents, such as CO₂H, ester, amide, and the like; -   halogen, such as chloro, fluoro, bromo, and the like -   fluorocarbonyl, such as CF₃, CF₂CF₃, and the like; -   phosphorous substituents, such as PO₃ ²⁻, and the like; -   sulfur substituents, including S-hydrocarbyl, SH, SO₃H,     SO₂-hydrocarbyl, SO₃-hydrocarbyl, and the like.

In certain embodiments, the number of non-hydrogen atoms is 6 or less in a substituent. In certain embodiments, the number of non-hydrogen atoms is 3 or less in a substituent. In certain embodiments, the number of non-hydrogen atoms on a substituent is 1.

In certain embodiments, the substituents contain only hydrogen, carbon, oxygen, halo, nitrogen, and sulfur. The substituents may contain only hydrogen, carbon, oxygen, and halo.

In certain embodiments A is —(CH₂)₆—, cis —CH₂CH═CH—(CH₂)₃—, or —CH₂C≡C—(CH₂)₃—, wherein 1 or 2 carbon atoms may be substituted with S or O; and E is C₁₋₆ alkyl, R², or —Y—R² wherein Y is CH₂, S, or O, and R² is aryl or heteroaryl.

In one embodiment R¹ is H, chloro, or fluoro. In one embodiment pR is H. In one embodiment, R¹ is chloro.

R² may be phenyl, naphthyl, biphenyl, thienyl, or benzothienyl having from 0 to 2 substituents selected from the group consisting of F, Cl, Br, methyl, methoxy, and CF₃.

R² may be CH₂-naphthyl, CH₂-biphenyl, CH₂-(2-thienyl), CH₂-(3-thienyl), naphthyl, biphenyl, 2-thienyl, 3-thienyl, CH₂-(2-(3-chlorobenzothienyl)), CH₂-(3-benzothienyl), 2-(3-chlorobenzothienyl), or 3-benzothienyl.

R² may be CH₂-(2-thienyl), CH₂-(3-thienyl), 2-thienyl, 3-thienyl, CH₂-(2-(3-chlorobenzothienyl)), CH₂-(3-benzothienyl), 2-(3-chlorobenzothienyl), or 3-benzothienyl.

While not intending to limit the scope of the invention in any way, compounds according to the structures below, wherein x is 0 or 1 and R¹ is H, chloro, fluoro, bromo, methyl, methoxy, or CF₃, are examples of prostaglandin EP₄ agonists.

While not intending to limit the scope of the invention in any way, compounds according to the structures below are examples of prostaglandin EP₄ agonists.

While not intending to limit the scope of the invention in any way, compounds according to the structures below are examples of prostaglandin EP₄ agonists.

While not intending to limit the scope of the invention in any way, compounds according to the structures below are examples of prostaglandin EP₄ agonists.

While not intending to limit the scope of the invention in any way, compounds according to the structures below, wherein x is 0 or 1 and R¹ is H, chloro, fluoro, bromo, methyl, methoxy, or CF₃, are examples of prostaglandin EP₄ agonists.

While not intending to limit the scope of the invention in any way, compounds according to the structures below are examples of prostaglandin EP₄ agonists.

Furthermore, the following United States Patent Applications or Patents, all of which are expressly incorporated by reference herein, disclose compounds which are prostaglandin EP₄ agonists: U.S. Pat. No. 6,552,067; U.S. Pat. No. 6,747,054; United States Patent Application Publication No. 20030120079; United States Patent Application Publication No. 20030207925; United States Patent Application Publication No. 20040157901; U.S. Pat. No. 4,117,014; United States Patent Application Publication No. 2004/0142969; U.S. Pat. No. 6,747,037; U.S. Pat. No. 6,610,719; U.S. Pat. No. 4,171,375; U.S. Pat. No. 3,931,297; United States Patent Application Ser. No. 821,705, filed Apr. 9, 2004; U.S. Pat. No. 6,670,485; U.S. Pat. No. 6,410,591; and U.S. Pat. No. 6,538,018.

All prostaglandin EP₄ agonists, pharmaceutically acceptable salts of all prostaglandin EP₄ agonists and prodrugs related to all prostaglandin EP₄ agonists are contemplated herein as prostaglandin EP₄ agonist components.

Prodrugs of prostaglandin EP₄ agonists comprising

are contemplated herein;

-   wherein R⁴ is H, halo or C₁₋₆ alkyl.

Halo is a group 7 atom such as fluoro, chloro, bromo, iodo, and the like.

C₁₋₆ alkyl is a linear, branched, or cyclic alkyl having from 1 to 6 carbons including, but not limited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclohexyl, and the like.

While not intending to limit the scope of the invention in any way, prodrugs of prostaglandin EP₄ agonists according to the structures below are contemplated.

The term carbohydrate is defined broadly to encompass simple sugars, disaccharides, oligosaccharides, polysaccharides, starches, and the like, whether linear, branched or macrocyclic. The term carbohydrate also refers to one of the foregoing classes of compounds having up to one amine functional group present for every six carbon atoms.

The esters, ethers, or amide prodrugs herein may incorporate either a direct bond to the carbohydrate or amino acids or may alternatively incorporate a spacer group including, but not limited to,

-   polyols such as ethylene glycol, glycerine, and the like, and     oligomers and polymers thereof; -   dicarboxylic acids, such as succinic acid, maleic acid, malonic     acid, azelaic acid, and the like; -   hydroxycarboxylic, acids such as lactic acid, hydroxyacetic acid,     citric acid, and the like; -   polyamines, such as ethylene diamine and the like; and -   esters, amides, or ethers to form combinations of any of the above.

In certain embodiments, the prodrug is a glucoside ester or ether. Thus, without limiting the scope of the invention in any way, compounds like those shown below, or pharmaceutically acceptable salts thereof, are useful as prostagiandin EP₄ agonist components in accordance with the present invention.

Alternatively, the ester or ether bond may occur at a different position on the sugar; i.e. the oxygen of one of the other hydroxyl groups is the oxygen of the ester or ether bond.

In one embodiment, the prodrug is a glucuronide ester or ether. Thus, without limiting the scope of the invention in any way, compounds like those shown below, or pharmaceutically acceptable salts thereof, are useful as prostaglandin EP₄ agonist components in accordance with the present invention.

Alternatively, the ester or ether bond may occur at a different position on the sugar; i.e. the oxygen of one of the other hydroxyl groups is the oxygen of the ester or ether bond.

Other prodrugs are cyclodextrin esters. Cyclodextrins are cyclic oligosaccharides containing 6, 7, or 8 glucopyranose units, referred to as α-cyclodextrin, β-cyclodextrin, or γ-cyclodextrin respectively (structures depicted below).

Thus, without limiting the scope of the invention in any way, compounds like those shown below, or pharmaceutically acceptable salts thereof, are useful as prostaglandin EP₄ agonist components in accordance with the present invention.

In any structure disclosed herein, CD indicates a cyclodextrin or a spacer-cyclodextrin, including α-, β-, and γ-cyclodextrin, which may be attached at a 2-, 3-, or 6- hydroxyl group. A 2-, 3-, or 6-hydroxyl group refers to the position on the glucose monomer where the anomeric carbon is 1 and the terminal carbon (in the chain form) is 6. The following examples illustrate this nomenclature.

For the compound below, CD is α-cyclodextrin linked at a 3-hydroxyl group.

For the compound below, CD is an ethylene glycol-β-cyclodextrin linked at a 2-hydroxyl group

For the compound below, CD is a y-cyclodextrin linked at a 6-hydroxyl group.

The CD esters shown below, as well as pharmaceutically acceptable salts thereof, are also useful prostaglandin EP₄ agonist prodrug compounds.

Dextran esters are also useful prodrugs. Dextran is a polymer of glucose primarily linked of α-D(1→6), i.e. D-glucose units are linked by a bond between an α-hydroxyl group at the anomeric (position 1) carbon and the hydroxyl group at carbon 6.

The dextran esters shown below are especially useful as prodrugs, as well as their pharmaceutically acceptable salts. Dx is dextran or spacer-dextran, where the O in CO₂ comes from a dextran hydroxyl group or from a spacer bonded to a dextran hydroxyl group, analogous to the structures shown for cyclodextrin esters.

Amino acid prodrugs are also contemplated, such as in the structures shown below, where R represents the side chain characteristic of a natural amino acid, and where R and the amide nitrogen may be connected as per proline. Pharmaceutically acceptable salts of compounds of these structures, whether anionic, cationic, or zwitterionic, are also useful.

In certain embodiments, R is selected from the group consisting of H, methyl, iso-propyl, sec-butyl, benzyl, indol-3-ylmethyl, hydroxymethyl, CHOHCH₃, CH₂CONH₂, p-hydroxybenzyl, CH₂SH, (CH₂)₄NH₂, (CH₂)₃NHC(NH₂)₂ ⁺, methylimidizol-5-yl, CH₂CO₂H, (CH₂)₂CO₂H and the like.

Ester prodrugs of EP₄ agonists may also be based upon amino acids, as demonstrated by the examples shown below. Pharmaceutically acceptable salts of compounds of these structures, whether anionic, cationic, or zwitterionic, are also useful.

Since amino acids such as serine, threonine, and tyrosine have hydroxyl functional groups in their side chains, ether prodrugs of EP₄ agonists based upon amino acids are also possible, as demonstrated in the examples below. Pharmaceutically acceptable salts of compounds of these structures, whether anionic, cationic, or zwitterionic, are also useful.

In addition, the spacers illustrated herein may be applied to amino acids to further increase the number and kinds of useful amino acid prodrugs.

Since a carbohydrate according to the definition given herein may have a limited amount of amine functional groups, carbohydrate amides are also possible such as the ones depicted below.

Analogous structures could also be drawn with any of the carbohydrate esters shown herein, making a large variety of carbohydrate amides possible for use in the methods disclosed herein. Further, since the prodrugs may incorporate an amine spacer, the number of carbohydrate amides contemplated is further diversified.

Prodrugs of the compounds shown below, and use of the compounds, or salts or prodrugs thereof, for any method, composition, or treatment disclosed herein, are specifically contemplated herein.

Unless indicated by a wedge or a dash, a carbon which has a chiral center can be construed to include the S isomer, the R isomer, or any mixture of isomers including a 50:50 R/S mixture. In particular, the pure isomers of each of the structures above, and any possible isomeric mixtures, including the 50:50 R/S mixtures, are contemplated. Methods of preparing these compounds are in U.S. Pat. No. 6,747,037 and U.S. Pat. No. 6,875,787, the disclosure of which are hereby incorporated in their entireties herein by reference.

There are a number of methods of preparing the prodrug compounds disclosed herein. While not intending to limit the scope of the invention in any way, a glucoside ether of a prostaglandin EP₄ agonist may be prepared from commercially available (Sigma Chemical Co.) 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside (2) by coupling the two in CCl₄ in the presence of silver carbonate, followed by hydrolysis of the ester protecting groups using a procedure adapted from Friend and Chang (J. Med. Chem. 1984, 27, 261-266; J. Med. Chem. 1985, 28, 51-57).

In this method, compound 1 is dissolved in dry CCl₄ or another suitable solvent, and freshly prepared Ag₂CO₃ (about 4.5 equivalents) is added. Compound 2 (about 2.7 equivalents) is then added dropwise while protecting the reaction mixture from light, and continuously distilling the solvent. The distilled solvent is replaced with fresh solvent during the course of the reaction. When the reaction is complete, the solution is worked up according to standard methods and purified by flash chromatography on RP-18 or another suitable purification method to yield compound 3. The ester groups of compound 3 are then saponified according to an art acceptable procedure such as NaOH in MeOH, and worked up and purified according to standard procedures.

This procedure may be used for prostaglandin EP₄ agonists having a single hydroxyl group. Alternatively, prodrugs for prostaglandin EP₄ agonists having more than 1 hydroxyl group may be prepared by protection of the hydroxyl groups with different groups, so that one may be removed for preparation of a prodrug. Generally, the ring, the α-chain, and the ω-chain are prepared separately and coupled toward the end of the synthetic procedure, so protection with distinct groups for each part is within the ability of a person of ordinary skill in the art.

A similar procedure may be used to prepare glucouronide ethers. Haeberlin et. al. (Pharmaceutical Research 1993, 10, 1553-1562) discloses such a procedure which may be adapted here.

The procedure shown below may be used to link prostaglandin EP₄ agonists to cyclodextrin or to another carbohydrate. Coupling of the succinic acid to cyclodextrin is carried out as described by Tanaka et. al. (Journal of Antibiotics 1994, 47,1025-1029), by suspending cyclodextrin in DMF, dissolving the mixture in pyridine, adding 1.2 equivalents of succinic anhydride, and stirring for 18 hours at room temperature. The mixture is poured into chloroform to precipitate the succinate ester product, which is filtered, washed with chloroform and methanol, and purified by an ODS column. Tanaka showed that reaction occurs preferentially at the 6 OH by a ratio of 4.6/1 for succinic anhydride. The preference reaction at the 6-OH is even greater for phthalic anhydride (13.6/1), naphthalene dicarboxylic anhydride (14.0/1), and cyclohexane dicarboxylic anhydride (14.7/1).

The hydroxyl group of the prostaglandin EP₄ agonist is activated by reacting with p-toluenesulfonyl chloride, and the tosylate 7 is reacted with the cyclodextrin derivative 6 to obtain the prodrug product.

Alternatively, cyclodextrin may be attached directly to the carboxylic acid of a prostaglandin EP₄ agonist as shown below. This procedure is an adaptation of one disclosed by Uekama and coworkers (J. Med. Chem. 1997, 40, 2755-2761 and Pharm. Pharacol. 1996, 48, 27-31) which described preparing cyclodextrin prodrugs of anti-inflammatory carboxylic acids such as 4-biphenylacetic acid. This procedure is readily adapted to prostaglandin EP₄ agonists. In this procedure, the cyclodextrin is reacted with p-toluensulfonyl chloride to form the tosylate 8, which is purified ion exchange chromatography followed by recrystallization from water. The hydroxyl groups of the prostaglandin are protected with THP by reaction with THPCI. Alternatively, a THP protected prostaglandin EP₄ agonist ester, which is frequently a late stage synthetic intermediate in the preparation of a prostaglandin EP₄ agonist, is saponified to give a THP protected free prostaglandin EP₄ agonist acid. The acid is then reacted with the cyclodextrin tosylate to give the desired prodrug, which is worked up and purified according to methods known in the art.

The procedure shown below may be used to line prostaglandin EP4 agonist analogs to dextran or to another carbohydrate. A procedure for the coupling of dexamethasone to dextran via a succinate linkage (McLeod et. al. Int J. Pharm. 1993, 92, 105-114) is readily adapted to the compounds herein. While not intending to limit the scope of the invention in any way, this procedure is most conveniently carried out with a prostaglandin EP₄ agonist having no free carboxylic acid (e.g. an ester) and 1 unprotected hydroxyl group. Connection to dextran to form the prodrug occurs at the free hydroxyl group. In this procedure, a hemisuccinate is formed from a hydroxyl group of a prostaglandin EP₄ agonist by adding it to succinic anhydride to form the hemisuccinate ester. The prostaglandin EP₄ agonist hemisuccinate is then reacted with 2 equivalents of 1,1 -carbonyidiimidizole for 30 minutes under nitrogen. Dextran and a base such as triethylamine is added and the reaction is stirred for about 21 hours at room temperature. Any protecting groups on other hydroxyl groups may then be removed by stirring in dilute acid or another method appropriate to the protecting group being used. The carboxylic acid need not be deprotected because the ester will readily hydrolyze in vivo.

The carbohydrates used in the procedures described above are easily varied or interchanged by a person of ordinary skill in the art. For example, glucoside and glucouronide esters of the carboxylic acid of the prostaglandin EP₄ agonist may be prepared using the tosylate of the carbohydrate in a procedure analogous to that described for cyclodextrin.

Amino acid prodrugs are readily obtained by many methods. For example, while not intending to be limiting, one of several procedures used for the coupling of salicylic acid to a methyl ester of alanine, glycine, methionine, or tyrosine (Nakamura et. al. J. Pharm. Pharmacol. 1992, 44, 295-299, and Nakamura et. al. Int. J. Pharm. 1992, 87, 59-66) can be adapted for use with prostaglandin EP₄ agonists. In this procedure, an equimolar amount of dicyclohexylcarbodiimide is added at or below 0° C. to a prostaglandin EP₄ agonist carboxylic acid and stirred about 30 minutes. An equimolar amount of the methyl ester of the amino acid is then added and stirred overnight at room temperature to form the amide. Deprotection of any hydroxyl group can then be carried out by using dilute aqueous acid or another method, depending on the protecting group.

A number of methods of delivering a drug to the gastrointestinal tract, or desired portion thereof, via oral dosage forms, for example, solid forms, semi-solid forms, aqueous and non-aqueous liquid forms, including but not limited to, emulsions, liquid suspensions, solutions and the like, are known in the art. These include, without limitation, 1) administration, for example, oral administration, of the drug with compatible excipients, for example, conventional excipients, including, without limitation, oils, such as hydrogenated caster oil, and the like and mixtures thereof; cellulosic derivatives and starch derivatives, such as alkyl celluloses, hydroxyl alkyl celluloses, alkali metal starch carboxylates, e.g., sodium starch glycolate, and the like and mixtures thereof; and sugars and sugar derivatives and the like and mixtures thereof; so that the drug is released in the upper gastrointestinal tract, for example, esophagus, stomach, duodenum, and the like, 2) administration, for example, oral administration, of a prodrug with compatible excipients, for example, conventional excipients, for example, as noted above, with the prodrug being selected so that the drug is released in the upper gastrointestinal tract and/or lower gastrointestinal tract, as desired, 3) coating the drug and/or prodrug with, or encapsulating or impregnating the drug and/or prodrug into, a polymer designed for delivery to the lower gastrointestinal tract, 4) time released delivery. of the drug and/or prodrug, 5) use of a bioadhesive system, and the like.

If desired, the presently useful compositions or dosage forms may additionally comprise other pharmaceutically acceptable excipients, such as tonicity components, buffer components, polyelectrolyte components, thickeners, fillers, diluents, flavoring agents, coloring agents, antioxidants, preservatives, such as antibacterial or antifungal agents, acids and/or bases to adjust pH, and the like and mixtures thereof. Each such additive, if present, may typically comprise about 0.0001% or less or about 0.01% or less to about 10% or more by weight of the composition. Such additives include those additives which are conventional and/or well known for use in similar pharmaceutical compositions. For example, suitable thickening agents include any of those known in the art, as for example pharmaceutically acceptable polymers and/or inorganic thickeners. Such agents include, but are not limited to, polyacrylate homo- and co-polymers; celluloses and cellulose derivatives; polyvinyl pyrrolidones; polyvinyl resins; silicates; and the like and mixtures thereof.

In one embodiment, the use of an azo-based prodrug may be employed to provide the drug in the lower gastrointestinal tract. Lower intestinal microflora are believed to be capable of reductive cleavage of an azo bond leaving the two nitrogen atoms as amine functional groups. Bacteria of the lower gastrointestinal tract also have enzymes which can digest glycosides, glucuronides, cyclodextrins, dextrans, and other carbohydrates, and ester prodrugs formed from these carbohydrates have been shown to deliver the parent active drugs selectively to the lower gastrointestinal tract.

Carbohydrate polymers including, without limitation, amylase, arabinogalactan, chitosan, chondroiton sulfate, dextran, guar gum, pectin, xylin, and the like and mixtures thereof, can be used to coat a drug and/or prodrug, or a drug and/or prodrug may be impregnated or encapsulated in the polymer. After oral administration, the polymers remain stable in the upper gastrointestinal tract, but are digested by the microflora of the lower gastrointestinal tract thus releasing the drug for therapeutic effect.

Polymers which are sensitive to pH may also be used since the lower gastrointestinal tract has a higher pH than the upper gastrointestinal tract. Such polymers are commercially available. For example, Rohm Pharmaceuticals, Darmstadt, Germany, markets pH dependent methacrylate based polymers and copolymers sold under the trademark Eudragit®, which have varying solubilities over different pH ranges based upon the number of free carboxylate groups in the polymer. Time release systems, bioadhesive systems, and other delivery systems may also be employed.

Coadministration of prostaglandin EP₄ agonists with one or more other, e.g., different, drugs, either in a single composition or in separate dosage forms, is also contemplated. While not intending to limit the scope of the invention in any way, other drugs which may be included in combination therapies with prostaglandin EP₄ agonists and their prodrugs include, but are not limited to:

-   Anti-inflammatory drugs, such as non-selective COX inhibitors and     selective COX-2 inhibitors including, diclofenac, flurbiprofen,     naproxen, suprofen, ibuprofen, ketorolac, piroxicam and the like and     mixtures thereof; indoles, such as indomethacin and the like;     diarylpyrazoles, such as celecoxib and the like; pyrrolo pyrroles;     other agents that inhibit prostaglandin synthesis; aminosalicylates;     other non-steroidal anti-inflammatory drugs, and the like and     mixtures thereof; -   Steroids, such as hydrocortisone, cortisone, prednisolone,     prednisone, dexamethasone, medrysone, fluorometholone, estrogens,     progesterones, and the like and mixtures thereof -   Immunomodulators, such as azathioprine, 6-mercaptopurine,     cyclosporine, and the like and mixtures thereof; and -   Humanized monoclonal antibodies against pro-inflammatorv cytokines,     such as infliximab, etanercept, onercept, adalimumab, CDP571,     CDP870, natalizumab, MLN-02, ISIS 2302, cM-T412, BF-5, vasilizumab,     daclizumab, basiliximab, Anti-CD40L, and the like and mixtures     thereof.

Such other drug or drugs are administered in amounts effective to provide the desired therapeutic effect or effects.

One useful assay for determining prostaglandin EP₄ activity and selectivity of compounds is described below.

Human Recombinant EP₁, EP₂, EP₃, EP₄, FP, TP, IP and DP Receptions: Stable Transfectants.

Plasmids encoding the human EP₁, EP₂, EP₃, EP₄, FP, TP, IP and DP receptors are prepared by cloning the respective coding sequences into the eukaryotic expression vector pCEP₄ (Invitrogen). The pCEP₄ vector contains an Epstein Barr virus (EBV) origin of replication, which permits episomal replication in primate cell lines expressing EBV nuclear antigen (EBNA-1). It also contains a hygromycin resistance gene that is used for eukaryotic selection. The cells employed for stable transfection are human embryonic kidney cells (HEK-293) that are transfected with and express the EBNA-1 protein. These HEK-293-EBNA cells (Invitrogen) are grown in medium containing Geneticin (G418) to maintain expression of the EBNA-1 protein. HEK-293 cells are grown in DMEM with 10% fetal bovine serum (FBS), 250 μg ml⁻¹ G418 (Life Technologies) and 200 μg ml⁻¹ gentamicin or penicillin/streptomycin. Selection of stable transfectants is achieved with 200 μg ml⁻¹ hygromycin, the optimal concentration being determined by previous hygromycin kill curve studies.

For transfection, the cells are grown to 50-60% confluency on 10 cm piates. The plasmid pCEP₄ incorporating cDNA inserts for the respective human prostanoid receptor (20 μg) is added to 500 μl of 250 mM CaCl₂. HEPES buffered saline ×2 (2×HBS, 280 mM NaCl, 20 mM HEPES acid, 1.5 mM Na₂ HPO₄, pH 7.05-7.12) is then added dropwise to a total of 500 μl, with continuous vortexing at room temperature. After 30 min, 9 ml DMEM are added to the mixture. The DNA/DMEM/calcium phosphate mixture is then added to the cells, which is previously rinsed with 10 ml PBS. The cells are then incubated for 5 hr at 37° C. in humidified 95% air/5% CO₂. The calcium phosphate solution is then removed and the cells are treated with 10% glycerol in DMEM for 2 min. The glycerol solution is then replaced by DMEM with 10% FBS. The cells are incubated overnight and the medium is replaced by DMEM/10% FBS containing 250 μg ml⁻¹ G418 and penicillin/streptomycin. The following day hygromycin B is added to a final concentration of 200 μg ml⁻¹.

Ten days after transfection, hygromycin B resistant clones are individually selected and transferred to a separate well on a 24 well plate. At confluence each clone is transferred to one well of a 6 well plate, and then expanded in a 10 cm dish. Cells are maintained under continuous hygromycin selection until use.

Radioligand Binding

Radioligand binding studies on plasma membrane fractions prepared from cells are performed as follows. Cells washed with TME buffer are scraped from the bottom of the flasks and homogenized for 30 see using a Brinkman PT 10/35 polytron. TME buffer is added as necessary to achieve a 40 ml volume in the centrifuge tubes. TME is comprised of 50 mM TRIS base, 10 mM MgCl₂, 1 mM EDTA; pH 7.4 is achieved by adding 1 N HCl. The cell homogenate is centrifuged at 19,000 rpm for 20-25 min at 4° C. using a Beckman Ti-60 or Ti-70 rotor. The pellet is then resuspended in TME buffer to provide a final protein concentration of 1 mg/ml, as determined by Bio-Rad assay. Radioligand binding assays are performed in a 100 μl or 200 μl volume.

The binding of [³H] PGE₂ (specific activity 165 Ci/mmol) is determined in duplicate and in at least 3 separate experiments. Incubations are for 60 min at 25° C. and are terminated by the addition of 4 ml of ice-cold 50 mM TRIS-HCl followed by rapid filtration through Whatman GF/B filters and three additional 4 ml washes in a cell harvester (Brandel). Competition studies are performed using a final concentration of 2.5 or 5 nM [³H] PGE₂ and non-specific binding is determined with 10-5 M unlabelled PGE₂.

For all radioligand binding studies, the criteria for inclusion are >50% specific binding and between 500 and 1000 displaceable counts or better.

The dosage of the prostaglandin EP₄ agonist component employed in accordance with the present invention varies over a relatively wide range and depends on a number of factors well known in the medicinal arts including, but not limited to, the weight of the individual to whom the agonist component is administered, the general health status/condition of such individual, the disease/condition sought to be treated/prevented by such administration, the severity of such disease/condition in such individual, the specific agonist component being administered, the sensitivity of such individual to the specific agonist component being administered, the mode of administration, the age of such individual, the sex of such individual, the pregnancy status of such individual, the other ongoing drug therapies being administered to such individual and the like factors.

The amount of prostaglandin EP₄ agonist component employed on a daily basis for each human or animal may be in a range of about 0.1 mg to about 30 mg or about 50 mg or about 100 mg or about 150 mg or about 200 mg or more. In one embodiment, such daily amount may be in a range of about 5 mg to about 150 mg or about 200 mg or more. The prostaglandin EP₄ agonist component may be administered in one or more doses daily, for example, once daily, twice daily, three times daily or more frequently. In one embodiment, once daily dosage is useful.

The duration of treatment with a prostaglandin EP₄ agonist component may vary over a wide range of times depending, for example, on factors many of which have been identified elsewhere herein. In general, the prostaglandin EP₄ agonist component is administered for a period of time sufficient to obtain the desired therapeutic effect or effects. The duration of treatment may be, for example, in a range of about 1 day or about 3 days or about 1 week or about 2 weeks to about 4 weeks or about 8 weeks or about 12 weeks or about 20 weeks or longer. In one useful embodiment, the duration of treatment is in a range of about 2 weeks to about 12 weeks.

The following non-limiting examples illustrate certain aspects of the present invention.

EXAMPLES 1 TO 5

A series of five (5) tablet compositions are produced using two (2) different prostaglandin EP₄ agonists and three (3) different prostaglandin EP₄ agonist prodrugs. Each of the tablet compositions is prepared as follows.

Within a dust containment area, a mixture of ingredients is prepared and blended until the mixture is uniform. The uniform mixture, having a composition as listed in the table directly below, is then used in a conventional tabletting machine to produce 100 mg tablets having such composition. The tablets may be packaged, for example, in high density polyethylene bottles, with appropriate silica gel packs, capped and labeled.

The mixtures and tablets have the following make-ups: Composition 1 2 3 4 5 Ingredient wt. % wt. % wt. % wt. % wt. % Prostaglandin EP₄ 10.0 — — — — Agonist 1⁽¹⁾ Prostaglandin EP₄ — 10.0 — — — Agonist Prodrug 1⁽²⁾ Prostaglandin EP₄ — — 10.0 — — Agonist 2⁽³⁾ Prostaglandin EP₄ — — — 10.0 — Agonist Prodrug 2⁽⁴⁾ Prostaglandin EP₄ — — — — 10.0 Agonist Prodrug 3⁽⁵⁾ Sugar 50.0 50.0 50.0 50.0 50.0 Excipients⁽⁶⁾ 40.0 40.0 40.0 40.0 40.0 (1)

(2) An isopropyl ester of (1) above. (3)

(4) An isopropyl ester of (3) above. (5) A methyl ester of (3) above. (6) A mixture of conventional pharmaceutical excipients useful, for example, as fillers, tabletting aids, bulking agents, preservatives, buffers and the like. Examples include, but are not limited to, mixtures of hydrogenated castor oil, hydroxyl ethyl cellulose, sodium starch glycolate, sorbitol and the like. Each of the tablets that is produced in Examples 1 to 5 includes about 10 mg of the agonist or prodrug, as the case may be, the total weight of each tablet being about 100 mg.

EXAMPLES 6 TO 9

A series of four (4) capsule compositions are produced using two (2) prostaglandin EP₄ agonists and two (2) prostaglandin EP₄ agonist prodrugs. Each of these capsule compositions is prepared as follows.

Within a dust containment area, small sugar spheres are provided. An aqueous mixture of the agonist or prodrug including a binder/sealer, such as Opadry® clear, is provided and is sprayed onto the sugar spheres using a conventional fluid bed spraying system. A second mixture including a binder/sealer, e.g., Opadry® clear, in a liquid carrier is sprayed onto the first sprayed spheres using a conventional fluid bed spraying system. This step results in agonist or prodrug loaded pellets with a sealing coat.

These pellets are coated with an aqueous mixture of triethyl citrate, talc and a methacrylic acid copolymer using a conventional fluid bed spraying system. This step results in agonist or prodrug loaded pellets with a sealing coat and an outer enteric coating. These pellets are encapsulated in natural transparent hard shell gelatin capsules. The filled capsules may be packaged, for example, in high density polyethylene bottles, with appropriate silica gel packs, capped and labeled.

The pellets with the enteric coating have the following make-ups. Composition 6 7 8 9 Ingredient wt. % wt. % wt. % wt. % Prostaglandin EP₄ 35.5 — — — Agonist 1⁽¹⁾ Prostaglandin EP₄ — 35.5 — — Agonist Prodrug 1⁽²⁾ Prostaglandin EP₄ — — 35.5 — Agonist 2⁽³⁾ Prostaglandin EP₄ — — — 35.5 Agonist Prodrug 2⁽⁴⁾ Sugar Spheres 33.5 33.5 33.5 33.5 Binder/Sealer 11.0 11.0 11.0 11.0 Methacrylic Acid 14.8 14.8 14.8 14.8 Copolymer⁽⁵⁾ Talc⁽⁶¹⁾ 3.7 3.7 3.7 3.7 Triethyl Citrate⁽⁷⁾ 1.5 1.5 1.5 1.5 (1)

(2) A dextran ester of (1) above. (3)

(4) A dextran ester of (3) above. (5) Enteric coating composition identified as Eudragit® L30-D55 sold by Rohm Pharmaceuticals. (6) Useful as a glidant (7) Useful as a plasticizer Each of the capsules that is produced in Examples 6 to 9 includes about 35.5 mg of the agonist or prodrug.

EXAMPLES 10 TO 14

Five adult humans are diagnosed with esophageal ulcers. Each of these people orally takes a tablet produced as described in Examples 1 to 5 having a different one of Compositions 1 to 5 once daily for twelve weeks. At the end of this period of time, each of the humans reports substantial relief from the esophageal ulcers. The pain and/or other symptoms of the ulcers have been reduced. In addition the ulcers have been reduced in size or substantially completely healed.

EXAMPLES 15 TO 19

Five adult humans are diagnosed with duodenal ulcers. Each of these people orallytakes a tablet (produced as described in Examples 1 to 5) having a different one of Compositions 1 to 5 once daily for twelve weeks. At the end of this period of time, each of the humans reports substantial relief from the duodenal ulcers. The pain and/or other symptoms of the ulcers have been reduced. In addition the ulcers have been reduced in size or substantially completely healed.

EXAMPLES 20 TO 24

Five adult humans are diagnosed with alcohol gastropathy. Each of these people orally takes a tablet (produced as described in Examples 1 to 5) having a different one of Compositions 1 to 5 once daily for twelve weeks. At the end of this period of time, each of the humans reports substantial relief from the alcohol gastropathy. The pain and/or other symptoms of this disease have been reduced.

EXAMPLES 25 TO 29

Five adult humans are diagnosed with non-steroidal anti-inflammatory drug induced gastropathy. Each of these people orally takes a tablet (produced as described in Examples 1 to 5) having a different one of Compositions 1 to 5 once daily for twelve weeks. At the end of this period of time, each of the humans reports substantial relief from the non-steroidal anti-inflammatory drug induced gastropathy. The pain and/or other symptoms of this disease have been reduced.

EXAMPLES 30 TO 33

Four adult humans are diagnosed with non-steroidal anti-inflammatory drug induced enteropathy. Each of these people orally takes a capsule (produced as described in Examples 6 to 9) containing pellets of a different one of Compositions 6 to 9 once daily for twelve weeks. At the end of this period of time, each of the humans reports substantial relief from the non-steroidal anti-inflammatory drug induced enteropathy. The pain and/or other symptoms of this disease have been reduced.

EXAMPLES 34 TO 37

Four adult humans are diagnosed with intestinal ischemia. Each of these people orally takes a capsule (produced as described in Examples 6 to 9) containing pellets of a different one of Compositions 6 to 9 once daily for twelve weeks. At the end of this period of time, each of the humans reports substantial relief from the intestinal ischemia. The pain and/or other symptoms of this disease have been reduced.

EXAMPLES 38 TO 40

Rat ileum epithelial cells identified as IEC-18, were purchased from ATCC. The cells were seeded and cultured overnight. In three (3) series of tests, each of PGE2, prostaglandin EP₄ agonist 1 and prostaglandin EP₄ agonist prodrug 3 was given at one or two concentrations to separate samples of the cells in a serum-free medium. One hour later, the non-steroidal anti-inflammatory drug (NSAID) indomethacin at 100 μM was added into the culture medium to induce apoptosis of the IEC-18 cells. Twenty four (24) hours after the addition of indomethacin, the cells were collected and processed for flow cytometry analysis. Ten thousand (10,000) cells were sorted for each sample, and the percentage of apoptotic cells was calculated. The results of this analysis/calculation are shown in FIG. 1, which shows the results as means with standard errors of the means.

As shown in FIG. 1, PGE2 reduced indomethacin-induced apoptosis by about 65%. Prostaglandin EP₄ agonist 1 and prostaglandin EP₄ agonist prodrug 3 also reduced indomethacin-induced apoptosis significantly.

EXAMPLE 41

Studies similar to those described for Examples 38 to 40 were conducted on cultured human gastric epithelial cells. This cell line, designated as AGS, was purchased from ATCC. Real-time RT-PCR showed that this cell type expresses four PGE2 subtype receptors, with EP₄ as the most abundant one. Prostaglandin EP₄ agonist 1 was given at four different concentrations to separate samples of the cells in a serum-free medium. One hour later, indomethacin at 400 μM was added into the culture medium in three of the samples to induce apoptosis of the AGS cells. Twenty four (24) hours after the addition of indomethacin, the cells were collected and processed for flow cytometry analysis. Ten thousand (10,000) cells were sorted for each sample, and the percentage of apoptotic cells was calculated. The results of this analysis/calculation are shown in FIG. 2, which shows the results as means with standard errors of the means.

As shown in FIG. 2, the test in which the prostaglandin EP₄ agonist 1 was used resulted in very little or substantially no apoptosis or cell death. Indomethacin itself induced about 30% apoptosis. The use of prostaglandin EP₄ agonist 1 reduced indomethacin-induced apoptosis significantly, for example, by about 30% to about 50%, depending on the dose employed.

EXAMPLES 42 TO 44

Another popular NSAID, aspirin, was used to induce apoptosis in cultured human gastric epithelial cells (AGS cells). Each of PGE2, prostagiandin EP₄ agonist 1 and prostaglandin EP₄ agonist prodrug 3 was given at one or two concentrations to separate samples of the AGS cells in a serum-free medium. One hour later, aspirin at 20 mM was added into the culture medium to induce apoptosis of the AGS cells. Twenty four (24) hours after the addition of aspirin, the cells were collected and processed for flow cytometry analysis. Ten thousand (10,000) cells were sorted for each sample, and the percentage of apoptotic cells was calculated. The results of this analysis/calculation are shown in FIG. 3, which shows the results as means with standard errors of the means.

As shown in FIG. 3, PGE2 and both prostaglandin EP₄ agonist 1 and prostaglandin EP₄ agonist prodrug 3 significantly decreased aspirin-induced apoptosis in the human gastric epithelial cells. The use of PGE2 and prostaglandin EP₄ agonist 1 reduced aspirin-induced apoptosis significantly, for example, by about 35% to about 70%, depending on the dose employed.

EXAMPLES 45 AND 46

Each of prostagiandin EP₄ agonist 1 and PGE 1 analog Misoprostol was given to C57BL/6 mice at two or three concentrations. Twenty four (24) hours and 30 minutes later, the NSAID indomethacin was given at 20 mg/kg to induce stomach lesions and stomach inflammation. Twenty four (24) hours after indomethacin dosing, the mice were sacrificed and the stomach lesions were scored histopathologically and by gross lesion count. The mean gross lesion scores with standard errors of the mean scores are shown in FIGS. 4 and 6.

As shown in FIG. 4, the test in which prostaglandin EP₄ agonist 1 was used resulted in significant reduction of the stomach lesions induced by indomethacin. These lesions manifested as bleeding, erosion, epithelial denuding and mucous ulcers located in the glandular region of the stomach. As shown in FIG. 6, the test in which the PGE1 analog Misoprostol was used resulted in significant reduction of indomethacin-induced stomach lesions. The use of the PGE1 analog Misoprostol and the prostaglandin EP₄ agonist 1 reduced indomethacin-induced stomach lesions significantly, for example, by about 50% to about 60%, depending on the dose employed.

The results of the histopathologic scores as means with standard errors of the means are shown in FIG. 6. As shown in FIG. 6 the tests in which prostaglandin EP₄ agonist 1 and PGE1 analog Misoprostol were used resulted in significant alleviation of indomethacin-induced injury to stomach tissue. The use of the prostaglandin EP₄ agonist 1 reduced indomethacin-induced stomach lesions significantly, for example, by about 40% to about 65%, depending on the dose employed.

The effect of treatment with the prostaglandin EP₄ agonist 1 on indomethacin-induced stomach edema and inflammation was evaluated. Increased stomach inflammation and edema resulted in increased stomach weight. The mean percentage of stomach weights as normalized to overall body weights with standard errors of the means are shown in FIG. 5. As shown in FIG. 5, the test in which the prostaglandin EP₄ agonist 1 was used resulted in mitigation of indomethacin-induced stomach inflammation and edema. The use of the prostaglandin EP₄ agonist 1 reduced indomethacin-induced stomach inflammation significantly, for example, by about 7% to about 10%, depending on the dose employed.

BrdU immunostaining was performed on stomach tissue sections from mice treated with the prostaglandin EP₄ agonist 1 and the PGE1 analog Misoprostol. Incorporation of BrdU label, as detected with positive BrdU immunostaining, is indicative of cell growth/regeneration. The abilities of prostaglandin EP₄ agonist 1 and the PGE1 analog Misoprostol to regenerate gastric epithelial cells when given prior to indomethacin dosing were compared. The mean percentages of BrdU label incorporated cells in stomach tissue sections and the standard errors of the means from both treatments are shown in FIG. 7. As shown in FIG. 7, the test in which the prostaglandin EP₄ agonist 1 was used resulted in significant restoration of the regenerative ability of gastric mucous cells, whereas the test in which the PGE1 analog Misoprostol was used did not. The use of prostaglandin the EP₄ agonist 1 markedly restored the regenerative ability of gastric mucous cells injured by indomethacin, for example, by about 25% at the maximum dose employed.

These tests demonstrate that prostaglandin EP agonist components are effective in mitigating one or more adverse effects of NSAIDs on the mucosal cells of the G.I. tract. These tests provide the evidence that prostaglandin EP agonist components are useful in treating NSAID-induced conditions of the G.I. tract, such as NSAID-induced gastroenteropathy.

All references, articles, patents, applications and publications set forth above are incorporated herein by reference in their entireties.

While this invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims. 

1. A method comprising administering a therapeutically effective amount of a prostaglandin EP₄ agonist component to a mammal afflicted with or prone to affliction with a disease or condition selected from the group consisting of an esophageal ulcer, alcohol gastropathy, a duodenal ulcer, non-steroidal anti-inflammatory drug-induced gastropathy, non-steroidal anti-inflammatory drug induced enteropathy and intestinal ischemia, thereby treating or preventing the disease or condition.
 2. The method of claim 1, wherein the prostaglandin EP₄ agonist component is administered to a gastrointestinal tract of the mammal.
 3. The method of claim 1, wherein the disease or condition is an esophageal ulcer
 4. The method of claim 1, wherein the disease or condition is alcohol gastropathy.
 5. The method of claim 1, wherein the disease or condition is a duodenal ulcer.
 6. The method of claim 1, wherein the disease or condition is non-steroidal anti-inflammatory drug-induced gastropathy.
 7. The method of claim 1, wherein the disease or condition is non-steroidal anti-inflammatory drug induced enteropathy.
 8. The method of claim 1, wherein the disease or condition is intestinal ischemia.
 9. The method of claim 1, wherein the prostaglandin EP₄ agonist component is selected from the group consisting of prostaglandin EP₄ agonists, pharmaceutically acceptable salts of prostaglandin EP₄ agonists, pro-drugs of prostaglandin EP₄ agonists and mixtures thereof.
 10. The method of claim 9, wherein the prostaglandin EP₄ agonists are selected from the group consisting of

and mixtures thereof: wherein a dashed line indicates the presence or absence of a bond; A is —(CH₂)₆—, cis —CH₂CH═CH—(CH₂)₃—, or —CH₂C≡C—(CH₂)₃—, wherein 1 or 2 carbon atoms may be substituted with S or O; or A is —(CH₂)_(m)—Ar—(CH₂)_(o)— wherein Ar is interarylene or heterointerarylene, the sum of m and o is from 1 to 4, and wherein one CH₂ may be substituted with S or O; X is S or O; J is C═O, CHOH, or CH₂CHOH; and E is C₁₋₁₂ alkyl, R², or —Y—R² wherein Y is CH₂, S, or O, and R² is aryl or heteroaryl.
 11. The method of claim 10, wherein A is —(CH₂)₆—, cis —CH₂CH═CH—(CH₂)₃—, or —CH₂C≡C—(CH₂)₃—, wherein 1 or 2 carbon atoms may be substituted with S or O; and E is C₁₋₆ alkyl R², or —Y—R² wherein Y is CH₂, S, or O, and R² is aryl or heteroaryl.
 12. The method of claim 11, wherein R² is phenyl, naphthyl, biphenyl, thienyl, or benzothienyl having from 0 to 2 substituents selected from the group consisting of F, Cl, Br, methyl, methoxy, and CF₃.
 13. The method of claim 12, wherein R² is CH₂-naphthyl, CH₂-biphenyl, CH₂—(2-thienyl), CH₂—(3-thienyl), naphthyl, biphenyl, 2-thienyl, 3-thienyl, CH₂—(2-(3-chlorobenzothienyl)), CH₂—(3-benzothienyl), 2-(3-chlorobenzothienyl), or 3-benzothienyl.
 14. The method of claim 9, wherein the prostaglandin EP₄ agonists are selected from the group consisting of

and mixtures thereof, wherein x is 0 or 1, and R¹ is H, chloro, fluoro, bromo, methyl, methoxy, or CF₃.
 15. The method of claim 9, wherein the prostaglandin EP₄ agonists are selected from the group consisting of

and mixtures thereof.
 16. The method of claim 1, wherein the prostaglandin EP₄ agonist component coprises at least one of

a pharmaceutically acceptable salt thereof, and a prodrug thereof.
 17. The method of claim 1, wherein the prostaglandin EP₄ agonist component comprises at least one of

a pharmaceutically acceptable salt thereof, and a prodrug thereof.
 18. The method of claim 1, wherein the prostaglandin EP₄ agonist component comprises a prodrug of

or a pharmaceutically acceptable salt thereof.
 19. The method of claim 1, wherein the prostaglandin EP₄ agonist component comprises a prodrug of

or a pharmaceutically acceptable salt thereof.
 20. A method of claim 1, wherein the prostaglandin EP₄ agonist component comprises a prod rug of a prostaglandin EP₄ agonist.
 21. The method of claim 20, wherein the prodrug is an ester, ether, or amide of a carbohydrate; or the prodrug is an ester, ether, or amide of an amino acid.
 22. The method of claim 20, wherein the prodrug is an amide, ester, or ether of an amino acid.
 23. The method of claim 1, wherein the prostaglandin EP₄ agonist component comprises a glucoside ester, ether, or amide; a glucuronide ester, ether, or amide; a cyclodextrin ester, ether, or amide; or a dextran ester, ether, or amide.
 24. The method of claim 1, wherein the prostaglandin EP₄ agonist component is selected from the group consisting of

, pharmaceutically acceptable salts thereof, prodrugs thereof and mixtures thereof.
 25. The method of claim 24, wherein the disease or condition is an esophageal ulcer
 26. The method of claim 24, wherein the disease or condition is alcohol gastropathy.
 27. The method of claim 24, wherein the disease or condition is a duodenal ulcer.
 28. The method of claim 24, wherein the disease or condition is non-steroidal anti-inflammatory drug-induced gastropathy.
 29. The method of claim 24, wherein the disease or condition is non-steroidal anti-inflammatory drug-induced enteropathy.
 30. The method of claim 24, wherein the disease or condition is intestinal ischemia. 